the closest you'd get to an Nblade from Babolat is the Pure Storm Ltd. GT but Babolats play stiffer than an Nblade. The other racquet you could give a try would be the YOUTEK speed 18x20 but again its stiffer and like the babolat the swingweight is much lower than the Nblade, unfortunately they were a pretty unique frame.

The nBlade has an interesting design with a firm hoop and a flexible throat. It seems to behave like a soft frame, but deliver the crisper feel you might expect from a something rather stiff. Two other frames I can think of with a similar design layout are the Fischer M Pro that mauricem mentioned and the Yonex RQiS 1 Tour.